El presente trabajo comprende la composición y distribución del plancton en las Islas Galápagos. Para el efecto se establecieron 13 estaciones ubicadas en las secciones 92° - 90° y 89° W, realizadas en mayo del 2004.The paper has reference of the composition and distribution of the species the phytoplankton and zooplankton around of Galapagos Islands. It was established 13 stations located in the sections folowing 92°-90° y 89° west, carry out during in may of 2004. It was identificated 58 species phytoplankton in water example and 70 species in net (50u). The diatoms were dominants and low concentration was registered the Dynoflagellates, Cocolitophorides, Silicoflagellates, Cianobacters, Tintinnoids. The cellular biomass were represented main the species Mesodinium rubrum y Gynodinium sp. that were the high abundance, coincidental with the species obtained of net example was registered Rhizosolenia hebetata and Thalassiosira subtilis that characteristic the most productivity in the sections 90° West and 1° sur. The zooplankton were registered 17 taxa of zooplankton representated the groups dominants the Copepods (35%), Chaetognaths (34%), and Zoeas of Brachiuras (11%) and it were frecuent around the Galapagos Islands. The species of chaetognathas was registered the dominance Sagitta enflata asociated S. pacifica with the hight density of individuals localizated in the section 90°W and 1° north in the surface. Aditionally it was registered the species Sagitta hexaptera determinance the hight abundance in the subsurface in the section 89°W between the 1° to 3° southeastern of the Galapagos Islands.